Source Serif 4: add source block to METADATA.pb

Assisted by an AI agent (Claude Opus 4.6)

diff --git a/ofl/sourceserif4/METADATA.pb b/ofl/sourceserif4/METADATA.pb
index e0e9f453e05df55b610136a2a7fd74fa2c198825..d11fa635f826bd90df219bf574e0fe83fff531a6 100644 (file)
--- a/ofl/sourceserif4/METADATA.pb
+++ b/ofl/sourceserif4/METADATA.pb
@@ -38,3 +38,7 @@ axes {
   min_value: 200.0
   max_value: 900.0
 }
+source {
+  repository_url: "https://github.com/adobe-fonts/source-serif"
+  commit: "b3980ade53bb3d023a0006076d05349236b309b1"
+}

diff --git a/ofl/sourceserif4/upstream_info.md b/ofl/sourceserif4/upstream_info.md
new file mode 100644 (file)
index 0000000..0cfc9d4
--- /dev/null
+++ b/ofl/sourceserif4/upstream_info.md
@@ -0,0 +1,39 @@
+# Source Serif 4 — Upstream Investigation
+
+**Model**: Claude Opus 4.6
+**Date**: 2026-03-12
+**Investigator**: AI agent (Claude) under guidance of @felipesanches
+
+## Summary
+
+The canonical upstream repository for Source Serif 4 was identified as
+`adobe-fonts/source-serif` on GitHub. The repository contained UFO source files
+on the `main` branch and was actively maintained by Adobe.
+
+## Repository
+
+- **URL**: https://github.com/adobe-fonts/source-serif
+- **Branch**: `main`
+- **Commit**: `b3980ade53bb3d023a0006076d05349236b309b1`
+- **Commit message**: "docs: re-shuffle content"
+
+## Source Format
+
+The `main` branch contained UFO sources in the `Roman/Masters/` and
+`Italic/Masters/` directory trees. UFO files were located at paths such as
+`Roman/Masters/text/master_0/SourceSerif_0.ufo`. Designspace files were also
+present (`Roman/SourceSerif4.designspace`). The `release` branch contained
+only compiled font binaries.
+
+## Decision
+
+The `source` block was added to `METADATA.pb` pointing to `adobe-fonts/source-serif`
+at commit `b3980ade53bb3d023a0006076d05349236b309b1` on the `main` branch.
+
+## Notes
+
+The designer listed in METADATA.pb is Frank Grießhammer. Source Serif 4 is an
+open-source serif typeface family created by Adobe, designed as a companion to
+Source Sans. It supports Latin, Cyrillic, and Greek scripts and is available
+as a variable font with `opsz` and `wght` axes. The typeface is licensed under
+the SIL Open Font License.